(1) Field of the Invention
The present invention relates to an insert that adapts a hand operated grease gun to receive a bellows type grease cartridge. In particular, the present invention provides a semi-rigid plastic adapter that is press fit into the pump housing of a manual grease gun and is connectible to a threaded outlet of a bellows type grease cartridge.
(2) Description of the Related Art
Manually operated high pressure grease guns of the type with which the present invention is used commonly comprise a dispensing barrel, a pump housing, and a grease supply tube casing. The dispensing barrel commonly has a nozzle fitting at its distal end for dispensing grease pumped from the gun. The proximal end of the barrel communicates with a manually operated pump contained in the pump housing. The pump is operated by a manual lever mechanism pivotally connected to the pump housing. Manipulating the lever mechanism dispenses grease contained in the supply tube casing of the gun, through the dispensing barrel. The tube casing is removably attached to a threaded grease supply opening of the pump housing by a series of screw threads provided at an open end of the casing. A spring biased piston housed in the tube casing supplies grease to the pump, and automatically decreases the volume of the tube casing as grease is dispensed from the gun.
Prior to using the grease gun, the operator of the gun first unscrews the tube casing from the grease supply opening of the gun pump housing, and retracts the piston in the casing . The operator then either packs grease in bulk in the open end of the tube casing, or inserts an open ended cylindrical grease cartridge into the tube casing. The operator then reassembles the casing to the pump housing by screwing the casing open end into the grease supply opening of the pump housing. The grease gun in now ready for use.
Grease guns of this type often have only a cast conduit in the interior of the pump housing supply opening that receives grease displaced from the casing by the spring biased piston. The conduit conducts the grease to the manually operated pump contained in the pump housing, which dispenses the grease from the gun under increased pressure.
Another type of manually operated grease gun includes a pump housing constructed with a conduit having a threaded socket in the housing grease supply opening. The threaded socket communicates the tube casing interior with the manual pump in the pump housing. This type of grease gun is specifically designed to be used with a bellows type grease cartridge that has a threaded dispensing outlet at one end. The operator unscrews the supply tube casing from the pump housing to expose the grease supply opening, and the threaded outlet of the bellows cartridge is screwed into the threaded socket provided in the supply opening of the gun pump housing. The spring biased piston is then retracted into the casing by pulling on a chain that extends from the closed end of the casing, and the casing is reassembled to the pump housing. This system is much easier to resupply with grease than prior art systems, for the operator need only unscrew an emptied grease cartridge from the threaded socket of the pump housing, and screw a new grease cartridge into the threaded socket before reassembling the casing to the housing. This prior art system is also cleaner to operate than other prior art systems in that the grease dispensed from the bellows cartridge is contained within the pump housing of the gun, and unlike previously used systems, the interior of the casing is not exposed to the grease.
One disadvantage found in the use of the bellows type grease cartridge is that it may only be used with the specific type of grease gun having the threaded socket that is connected to the threaded dispensing outlet of the cartridge. Prior art grease guns not specifically designed with a threaded socket for connection to the threaded dispensing outlet of the bellows grease cartridge cannot be used with this cartridge.
The present invention overcomes the disadvantages associated with the bellows type grease cartridge by providing an insert for grease guns that are not specifically designed for use with the bellows type grease cartridge, that adapts the grease gun for use with such a cartridge.
It is therefore an object of the present invention to provide an adapter that is inserted into the pump housing of a grease gun, that provides a sealing partition between the interior of the pump housing and the interior of the grease supply tube casing, that provides a threaded connection that is dimensioned to receive the threaded dispensing outlet of a bellows type grease cartridge, and that adapts the grease supply opening of the grease gun pump housing for connection to a threaded outlet of a bellows type grease cartridge.